Radially expandable stents are widely used medical devices. A stent typically is a cylindrically shaped device formed from wire(s) or a tube and intended to act as a permanent prosthesis. A typical stent ranges from about 5 millimeters to about 50 millimeters in length. A stent is deployed in a body lumen from a radially compressed configuration into a radially expanded configuration that allows it to contact and support a body lumen. Optionally, a balloon of appropriate size and pressure can be used to open a lesion prior to delivery of the stent to its intended location.
It is known in the art of fabricating medical devices to coat stents with coating materials chosen to impart a variety of desirable properties to the device. For example, coatings have been applied to stents to improve mechanical properties and to provide for drug release and for biocompatibility. Since fabrication of a radially expandable stent from wire requires the wire to be mechanically bent a multitude of times, it is generally preferred to apply the coating to the prefabricated stent to avoid the resultant coating breaks and adhesion failures that frequently result from bending a precoated wire. As a result, the costs for applying coatings to prefabricated stents, along with the resulting coating quality, are largely controlled and limited by the fact that a batch process is being used to coat irregularly shaped objects.
A few reports of the fabrication of stents from wires that have been precoated with specific polymeric layers have appeared in the art, some examples of which may be found in the issued U.S. Patents listed in Table 1 below.
TABLE 1Prior Art PatentsPatent No.Inventor(s)Issue Date6,113,621Wiktor5 Sep. 20006,106,454Berg et al.22 Aug. 20006,100,474McGregor et al.8 Aug. 20006,077,413Hafeli et al.20 Jun. 20005,980,551Summers et al.9 Nov. 19995,968,091Pinchuk et al.19 Oct. 19995,865,814Tuch2 Feb. 19995,843,158Lenker et al.1 Dec. 19985,837,313Ding et al.17 Nov. 19985,837,008Berg et al.17 Nov. 19985,824,048Tuch20 Oct. 19985,776,184Tuch7 Jul. 19985,722,984Fischell et al.3 Mar. 19985,679,400Tuch21 Oct. 19975,624,411Tuch29 Apr. 19975,607,463Schwartz et al.4 Mar. 19975,591,224Schwartz et al.7 Jan. 19975,554,181Das10 Sep. 19965,545,211An et al.13 Aug. 19965,527,354Fontaine et al.18 Jun. 19965,525,356Jevne et al.11 Jun. 19965,464,650Berg et al.7 Nov. 19955,449,372Schmaltz et al.12 Sep. 19955,356,433Rowland et al.18 Oct. 19945,336,518Narayanan et al.9 Aug. 19945,330,500Song19 Jul. 19945,163,958Pinchuk17 Nov. 19925,059,166Fischell et al.22 Oct. 19914,886,062Wiktor12 Dec. 19894,795,458Regan3 Jan. 1989
All patents listed in Table 1 above are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and claims set forth below, many of the devices and methods disclosed in the patents of Table 1 may be modified advantageously by using the teachings of the present invention.
U.S. Pat. No. 6,113,621 (Wiktor) discloses the fabrication of stents from polyester-coated copper wire. U.S. Pat. No. 5,968,091 (Pinchuk et al.) discloses the fabrication of stents from extrusion coated fluorinated ethylene propylene (FEP) polymer on tantalum wire. However, stents that have been fabricated from wires that have been precoated with polymeric hydrogel coatings are unknown in the art.